May 16 (Reuters) - The U.S. Justice Department for the
second time in a month sued UnitedHealth Group Inc on
Tuesday, accusing the nation's largest health insurer of
obtaining over $1 billion from Medicare to which it was not
entitled.

The complaint, filed in federal court in Los Angeles, came
after the Justice Department brought a separate but similar case
against UnitedHealth. In both cases, the government intervened
in whistleblower lawsuits against UnitedHealth.

The latest complaint came after the Justice Department
intervened in a lawsuit brought by former UnitedHealth executive
Benjamin Poehling, whose whistleblower case was filed under seal
in 2011.

UnitedHealth had no immediate comment. It previously said it
rejects the claims in the underlying whistleblower lawsuit and
would fight the claims vigorously.

Medicare, a government health insurance program, serves more
than 50 million Americans who are elderly or disabled. More than
one-third of them are in Medicare Advantage plans run by private
insurers like UnitedHealth.

In the lawsuit, the Justice Department alleged that
UnitedHealth obtained inflated risk adjustment payments based on
untruthful and inaccurate information about the health status of
patients enrolled in its Medicare Advantage plans.

The lawsuit said UnitedHealth's conduct damaged the Medicare
program by over $1.14 billion from 2011 to 2014. The Justice
Department said it is seeking triple damages under the False
Claims Act as well as penalties.

Poehling filed his lawsuit under the False Claims Act, which
allows whistleblowers to sue companies on the government's
behalf to recover taxpayer money paid out based on fraudulent
claims.

If successful, whistleblowers receive a percentage of the
recovery. A government decision to intervene is typically a
major boost to such cases.

Poehling also sued other insurers, claiming that they along
with UnitedHealth had defrauded the United States of hundreds of
millions - and likely billions - of dollars through claims for
payments from Medicare for the elderly.

While the Justice Department has not pursued claims against
other companies, in March it said it was investigating Centene
Corp's Health Net Inc, Aetna Inc, Cigna Corp's
Bravo Health Inc and Humana Inc.

The Justice Department has also intervened in a related
whistleblower lawsuit brought by James Swoben, a former Senior
Care Action Network Health Plan employee and a consultant to the
risk adjustment industry.

The case is U.S. ex rel. Benjamin Poehling v. UnitedHealth
Group Inc et al, U.S. District Court, Central District of
California, No. 16-cv-08697.
(Reporting by Nate Raymond in Boston; Editing by Leslie Adler)